The invention is based on a hydraulic machine tool as generically defined by the preamble to the main claim. In a known machine tool of this generic type (German Patent 43 01 983), the work stroke of the work piston is braked by causing the step of greatest diameter, namely of the work piston, that serves the purpose of the rapid traverses to strike the bottom of the corresponding pneumatic work chamber; there is a damping disk on the face of the work piston, but it accomplishes only slight damping.
Machine tools of this generic type are intrinsically high-speed, energy-saving pneumatic systems, with which a hydraulic system is integrated, by means of which latter, after a desired forward stroke in the working direction, a power stroke with very high adjusting force is attainable. Although only pneumatic connections to outside the housing of the machine tool are available, the pressure intensification is accomplished with the aid of the hydraulics. As a result, hydraulic chambers along with pneumatic chambers move in the piston stroke direction, which involves the not-inconsiderable problem of sealing the one off from the other. Air that gets into the hydraulic fluid leads to undesired compressibility of the oil; oil leaking out of the hydraulic portion can cause functional failures.
Damping the work stroke, and sometimes the return stroke as well, remains a problem in such machine tools, which use hydropneumatic pressure intensification. Especially whenever a sheet-metal connection, for instance, is to be made via a suitable tool, and upon idling the step piston, pounds into one of its terminal positions with full force, the result cannot only be considerable noise but also attendant damage. Even though this is an old, widespread problem in such machine tools, aside from the aforementioned elastic disk no damping that in particular is also adjustable to the weight or mass of the tool has yet been found.